颈静脉孔的显微外科解剖研究

目的研究颈静脉孔的硬脑膜结构和孔内神经、血管结构的行程及形态特征。方法显微镜下模拟枕下极外侧入路、颈-乳突入路和Fisch颞下窝入路的手术操作，研究10例福尔马林及乳胶灌注头颈标本颈静脉孔的显微解剖特征。结果在颈静脉孔的颅内开口，舌咽神经与迷走、副神经间被纤维或骨性结构隔开。在颈静脉孔内，脑神经行于颈静脉球上方的内侧，舌咽神经位于最前方，所有神经束均可用显微外科技术分开，副神经的脑根同脊髓根一起进入颈静脉孔后又加入迷走神经。颈静脉球及临近颈内静脉接受来自乙状窦、岩下窦、椎静脉丛、舌下神经管静脉丛、髁导静脉及岩斜下静脉的静脉回流。结论颈静脉孔的颅内开口可分为岩部、颈内部(或神经部)和乙状窦部．颈静脉孔内脑神经的不同神经纤维束在整个行程中彼此独立，副神经仅由脊髓根构成。     

Anatomical study of jugular foramen in the neck

IntroductionThe anatomical complexity of the jugular foramen makes surgical procedures in this region delicate and difficult. Due to the advances in surgical techniques, approaches to the jugular foramen became more frequent, requiring improvement of the knowledge of this region anatomy.ObjectiveTo study the anatomy of the jugular foramen, internal jugular vein and glossopharyngeal, vagus and accessory nerves, and to identify the anatomical relationships among these structures in the jugular foramen region and lateral-pharyngeal space.MethodsA total of 60 sides of 30 non-embalmed cadavers were examined few hours after death. The diameters of the jugular foramen and its anatomical relationships were analyzed.ResultsThe diameters of the jugular foramen and internal jugular vein were greater on the right side in most studied specimens. The inferior petrosal sinus ended in the internal jugular vein up to 40 mm below the jugular foramen; in 5% of cases. The glossopharyngeal nerve exhibited an intimate anatomical relationship with the styloglossus muscle after exiting the skull, and the vagal nerve had a similar relationship with the hypoglossal nerve. The accessory nerve passed around the internal jugular vein via its anterior wall in 71.7% of cadavers.ConclusionAnatomical variations were found in the dimensions of the jugular foramen and the internal jugular vein, which were larger in size on the right side of most studied bodies; variations also occurred in the trajectory and anatomical relationships of the nerves. The petrosal sinus can join the internal jugular vein below the foramen.     

A rare case of jugular foramen schwannoma arising from Jacobson's nerve

The jugular foramen (JF) region is a complex area of the cranial base where venous structures such as the jugular bulb and the inferior petrosal sinuses are strictly related to the lower cranial nerves IX, X and XI. The most common tumours include glomus jugulare, schwannomas of the mixed cranial nerves (IX-XI) and meningiomas. Schwannomas involving the jugular foramen are rare neoplasms and in most of the cases are thought to originate from the X cranial nerve. We report a case of a schwannoma of the JF diagnosed at an early stage, allowing radiological and surgical evidence to support its origin from the tympanic branch of the IX cranial nerve. To our knowledge this is the first case reported in the literature of such a tumour.     

Parapharyngeal space schwannomas: preoperative imaging determination of the nerve of origin

OBJECTIVES: To determine if preoperative radiographic cross-sectional images can predict the nerve of origin of a parapharyngeal schwannoma and, specifically, whether it originates from the vagus nerve or the cervical sympathetic chain. DESIGN: A retrospective review. SETTING: Academic medical center. PATIENTS: The study population comprised 12 patients who underwent surgical resection of schwannomas of the parapharyngeal space. The nerve of origin was identified based on operative findings and postoperative physical examinations. Of the 12 patients, 11 underwent preoperative magnetic resonance imaging and 1 underwent preoperative contrast-enhanced computed tomography. A CAQ (Certificate of Added Qualification)-certified neuroradiologist reviewed the imaging studies, blinded to the surgically determined nerve of origin. For each case, it was predicted whether the tumor arose from the vagus nerve or sympathetic chain based on the location of the schwannoma with reference to the carotid sheath vessels. MAIN OUTCOME MEASURE: Identification of the nerves of origin using the displacement of vessels as a marker. RESULTS: At the time of operation, it was determined that 5 patients (42%) had schwannomas from the cervical sympathetic chain and 7 patients (58%) had schwannomas of the cervical vagus nerve. By imaging, the nerve of origin was successfully determined in 4 of 5 cases of sympathetic chain schwannoma (80%) and in 7 of 7 cases of vagal nerve schwannoma (100%). Schwannomas of the cervical sympathetic chain were found to displace both the carotid and jugular vessels without separating them. Vagal nerve schwannomas were found to separate the carotid arteries from the internal jugular vein. A vagal nerve schwannoma may also displace the sheath vessels posteriorly, without splaying them. CONCLUSIONS: Carotid and jugular vessel displacement, as determined by cross-sectional imaging, can predict the likely nerve of origin of a parapharyngeal space schwannoma. This determination allows for effective preoperative counseling regarding the expected sequelae of surgical resection.     

Jugular foramen schwannomas: diagnosis, management, and outcomes

OBJECTIVES/HYPOTHESIS: To describe the presentation, radiographic findings, and surgical management of seven patients who have been diagnosed and treated with jugular foramen schwannomas at the University of Utah. STUDY DESIGN: Retrospective chart review. METHODS: The charts of seven patients diagnosed with jugular foramen schwannomas were reviewed for presentation symptoms, radiographic findings, and physical examination findings. For the six who underwent surgical excision, the surgical procedure used, cranial nerve function results, audiometric results, perioperative complications, and other follow-up data are presented. RESULTS: Seven patients were identified from ages 24 to 69 years. Six of the seven underwent surgical excision. Primary presentation symptoms included dizziness, hearing loss, dysphagia, diplopia, tongue paresis, and hoarseness. The choice of surgical approach was based on the size and location of the tumor. All patients had complete excision of their tumors. The nerve of origin included the glossopharyngeal, vagus, and spinal accessory nerves. Preoperative cranial nerve dysfunction continued postoperatively for lower cranial nerves but resolved in patients who were noted to have preoperative dysfunction of cranial nerve V and VI. The rate of new lower cranial nerve injury was 15% and was only seen in the cranial nerves that were determined to be the nerve of origin. In two cases, a temporary feeding tube was required. No recurrences have been noted to date. CONCLUSIONS: Jugular foramen schwannomas can be successfully diagnosed preoperatively with computed tomography and magnetic resonance imaging. These tumors can be successfully managed with surgery and low morbidity.     

Accessory nerve schwannoma extending extracranially to the second cervical level of vertebra

We described a 67-year-old man who had a right jugular foramen tumour expanding extracranially to the level of C2 cervical body. Paralysis of the glossopharyngeal, vagal, accessory, hypoglossal nerves and sensorineural hearing disturbance were found. The tumour originated from the accessory nerve and the histological examination revealed it was schwannoma. Accessory nerve as an origin of the jugular foramen neurinoma and its pre-operative neurological signs are reviewed.     

Differentiation Between Schwannoma of the Vagus Nerve and Schwannoma of the Cervical Sympathetic Chain by Imaging Diagnosis

Ultrasonography, computed tomography, and magnetic resonance imaging were performed to differentiate preoperatively between schwannomas of the vagus nerve and schwannomas of the cervical sympathetic chain by observing the position of schwannomas in regard to the surrounding blood vessels. Ultrasonography also permitted direct visualization of the vagus nerve, so its position relative to the schwannoma could be examined. In schwannomas of the vagus nerve the schwannoma grew between the common carotid artery and the internal jugular vein or between the internal carotid artery and the internal jugular vein, resulting in an increase in the distance between the artery and vein (separation). In schwannomas of the cervical sympathetic chain, no separation was observed between the internal jugular vein and the common carotid artery or internal carotid artery. Ultrasonography with a 7.5-MHz transducer showed the derivation of the tumor from the vagus nerve in schwannomas of the vagus nerve but showed the vagus nerve on the tumor surface in schwannomas of the cervical sympathetic chain.     

乙状窦后径路舌咽神经切断术治疗舌咽神经痛

目的 分析26例舌咽神经痛的临床特征，探讨舌咽神经痛的诊断、治疗方法和注意事项。方法 采用经乙状窦后入路进入小脑脑桥角，在手术显微镜下对颈静脉孔周围进行探查并切断舌咽神经根；伴有耳痛者同期切断迷走神经上支；如发现占位病灶须切除病灶并行病理检查。结果 术中发现3例舌咽神经表面有小脑后下动脉压迫；2例舌咽神经根周围有明显的蛛网膜增厚、粘连；2例小脑脑桥角占位性病变，病检为脑膜瘤和脉络丛乳头状瘤。术后随访0．5～5年，平均3．9年，除3例复发外，其余患者舌咽神经痛症状完全消失。所有患者术后均遗有术侧轻度舌后1／3麻木不适感，1例术后出现急性呼吸功能衰竭，经气管切开后治愈，未出现其他并发症及后遗症。3例复发者再次手术，将迷走神经上支切断，分离舌咽神经纤维断端与邻近迷走神经的粘连，并用双极电凝烧灼断端，术后疼痛彻底消失。结论 对确诊的舌咽神经痛，乙状窦后径路舌咽神经切断术是比较理想的选择，但要重视对可能因累及神经、断端双极电凝烧灼以及老年病人手术风险的评估。     

Conservative facial nerve management in jugular foramen schwannomas

OBJECTIVE: Although transposition of the facial nerve is crucial in infiltrative vascular lesions involving the jugular foramen, the objective was to show that a conservative approach to management of the facial nerve is sufficient with jugular foramen neuromas because of their noninfiltrative, less vascular nature and medial location in the jugular foramen. STUDY DESIGN: Retrospective case review. SETTING: Tertiary, private, multiphysician, otologic practice. PATIENTS: Sixteen patients with jugular foramen schwannoma (18 procedures) treated between January 1975 and October 1995. The 8 male and 8 female patients ranged in age from 13 to 66 years (mean age 47.7 years). INTERVENTION: One-stage, total jugular foramen neuroma removal without transposition of the facial nerve, using a variety of surgical approaches. MAIN OUTCOME MEASURES: Facial nerve transposition (yes or no), House-Brackmann facial nerve grade, lower cranial nerve status, complications. RESULTS: One-stage total tumor removal was accomplished in all the cases. In 13 (72%) of the neuromas, removal was accomplished without facial nerve transposition. Transposition was performed in 2 revision cases in which scar tissue from a previous operation prevented complete control of the carotid artery and safe removal, 2 cases with large tumor extension anteriorly to the petrous apex, and 1 case with extensive involvement of the middle ear. A House-Brackmann facial nerve Grade I or II was obtained in 16 of the 18 procedures, with 1 Grade III and 1 case that remained Grade V, as it was preoperatively. CONCLUSIONS: One-stage, total tumor removal can be achieved with excellent control of the important vascular structures and without transposition of the facial nerve in a majority of jugular foramen schwannomas.     

Middle ear schwannoma--case report

Schwannoma is one of the common benign middle ear space tumors. The tumors may present with facial nerve paresis or palsy, otologic symptoms and/or parotid mass middle ear schwannomas may originate from the nerves of the tympanic caviti or by extensions from outside the middle ear space. Schwannomas of the facial nerve can occur along any segment, but they frequently involve the geniculate ganglion and extend proximally or distally from there. MRI and CT imaging characteristics are similar to those of vestibular schwannomas. We present the clinical and radiologic features of a middle-space schwannoma originating from facial nerve. The patient underwent middle ear exploration and mastoidectomy. The tumor was of facial nerve origin and was separated from middle ear. The pathologic diagnosis was schwannoma.     

Schwannomas of the parapharyngeal space and jugular foramen

Schwannomas or neurilemmomas are among the most common neoplasms occupying the parapharyngeal space, yet only 107 cases have been previously reported. Neurilemmomas involving the jugular foramen are extremely rare. Only 55 cases have been reported in the world literature. The neoplasm occurred in the parapharyngeal space in three of our patients and in the jugular foramen in another patient. Of the tumors located in the parapharyngeal space, the nerve of origin in one of them was the glossopharyngeal, which is extremely rare. Adequate exposure for complete excision of parapharyngeal space tumors is best obtained through an external incision and should not be attempted transorally. In the jugular foramen case, the neoplasm arose from the vagus nerve high in the neck and extended intracranially in a “dumbbell” shape into the posterior cranial fossa. Total removal was successfully accomplished in one stage, by using a subtotal temporal bone resection — upper neck — posterior cranial fossa approach. Surgical removal is the treatment of choice. Schwannomas rarely recur following complete excision.     

颈静脉孔神经鞘瘤的外科治疗

目的 探讨颈静脉孔神经鞘瘤的手术入路及治疗效果。方法 回顾性分析采用显微外科手术治疗颈静脉孔神经鞘瘤２４例,其中颅内型（Ａ型）：肿瘤主体位于桥小脑角（１２例）;骨内型（Ｂ型）：肿瘤主体位于颈静脉孔内,向颅内生长（５例）;颅外型（Ｃ型）：肿瘤主体位于颅外,并向颈静脉孔生长（１例）;混合型（Ｄ型）：肿瘤由颈静脉孔向颅内外生长,呈哑铃型（６例）。Ａ型采用枕下乙状窦后入路,Ｂ型采用远外侧入路,Ｃ型和Ｄ型采     

Extracranial head and neck schwannomas--a 10-year review

OBJECTIVES: To present our experience in managing a large case series of extracranial schwannomas highlighting presenting features, diagnostic difficulties, and outcomes associated with surgical treatment of these tumours. METHOD: A retrospective case note study of 31 patients with a diagnosis of extracranial schwannoma seen in the Department of Otolaryngology, Head and Neck Surgery at Southmead Hospital, a tertiary referral centre and University hospital between 1 June 1993 and 30 May 2003. RESULTS: The commonest anatomical location was in the neck (42%) and an isolated neck lump was the commonest presentation (77%). Pressure symptoms were the next most common mode of presentation, and were often a helpful indicator of the nerve of origin. The nerve of origin was identified in 47% of patients who underwent surgery. Immunohistochemistry was a useful tool in the diagnosis of these tumours and magnetic resonance imaging was the preferred imaging technique to delineate their extent. The most significant postoperative morbidity was associated with the schwannomas of the vagus nerve, sympathetic chain, hypoglossal nerve, glossopharyngeal nerve and the facial nerve. CONCLUSION: Schwannomas can present in a wide variety of sites within the head and neck region and therefore it is important that otolaryngologists and head-neck surgeons are familiar with the more common sites of presentation and the potential difficulties associated with the diagnosis and management of these tumours. Adequate imaging should be carried out preoperatively to gain as much information as possible about the individual tumour and allow informed patient counseling regarding to potential risks and morbidity of surgical intervention.     

Endoscopic nasal surgery for pterigopalatine fossa schwannoma

Schwannomas are tumors of nerve sheath origin, the lesion being derived from the Schwann cells surrounding neural tissue in most of the peripheral, cranial and autonomic nerves. Schwannomas occurring in the head and neck represent 25-35% of all reported schwannomas, and most commonly arise from the acoustic or the neumogastric nerves. In the nose and paranasal sinuses these tumors are very uncommon (fewer than 4% of all schwannomas). In the pterygopalatine fossa they are very rare, and arise in this case from the ophthalmic and maxillary branches of the trigeminal nerve. In this exceptional site, the tumor is classically approached through a Caldwell-Luc incision. In this case, we report the removal of a schwannoma of the pterygopalatine fossa by endoscopic sinus surgery.     

Splaying of the carotid bifurcation caused by a cervical sympathetic chain schwannoma

Splaying of the carotid bifurcation revealed by an imaging study is usually indicative of a carotid body tumor, but there are other possibilities. To promote awareness of a cervical sympathetic chain schwannoma as another cause of splaying of the carotid bifurcation, we present a case of cervical sympathetic chain schwannoma, with an additional 7 cases in the English-language literature, and discuss the relationship between the great vessels of the neck and a carotid body tumor or a schwannoma of the cervical sympathetic chain or vagus nerve from an anatomic viewpoint. We conclude that splaying of the carotid bifurcation with hypervascularity suggests a carotid body tumor, whereas in cases without hypervascularity, a cervical sympathetic chain schwannoma is another possibility. Vagus nerve schwannomas can separate the internal jugular vein and internal carotid artery, but seldom widen the carotid bifurcation.     

Surgical management of jugular foramen schwannomas with hearing and facial nerve function preservation: a series of 23 cases and review of the literature

OBJECTIVE: Schwannomas of the jugular foramen are rare lesions and controversy regarding their management still exists. The objective of this retrospective study was to analyze the management and outcome in a series of 23 cases collected at a single center. SETTING: This study was conducted at a quaternary private otology and skull base center. METHODS: Charts belonging to patients with a diagnosis of jugular foramen schwannoma attending our center between May 1988 and April 2006 were examined retrospectively. RESULTS: The study group consisted of 23 patients. One patient (a 73-year-old woman) with normal lower cranial nerves function was managed with watchful expectancy and regular clinical and radiologic follow ups. The infratemporal fossa approach-type A (IFTA-A) was performed in 3 cases. One patient underwent a transcochlear-transjugular approach. Of the 22 patients surgically treated, 12 patients were operated on by the petrooccipital transsigmoid approach (POTS). In one patient with a preoperative dead ear, a combined POTS-translabyrinthine approach was adopted. Two patients were operated on through the POTS approach combined with the transotic approach. In another case (a 67-year-old woman), a subtotal tumor removal through a transcervical approach was planned to resect a 10-cm mass in the neck. One patient underwent a first-stage combined transcervical-subtotal petrosectomy approach to remove a huge tumor in the neck; the second-stage intradural removal of the tumor was accomplished through a translabyrinthine-transsigmoid-transjugular approach. The last patient underwent a first-stage combined transcervical-subtotal petrosectomy approach to remove the neck tumor component; this patient is now waiting for the second-stage intradural removal of the tumor. Complete tumor removal was accomplished in 21 cases and in one case, a residual schwannoma was left in place in the area of the jugular foramen. The 3 patients who were operated on by IFTA-A underwent permanent anterior transposition of the facial nerve. At 1-year follow up, 2 of these patients had House-Brackmann grade I and 1 reached grade IV. The patient who underwent a transcochlear-transjugular approach had a permanent posterior transposition of the facial nerve. At 1-year follow up, he had grade III facial nerve function. Postoperative facial nerve function was normal (House-Brackmann grade I) in all patients operated on by the POTS approach. Twelve patients had hearing-preserving surgery using the POTS approach. Good hearing was preserved in 10 cases (83.3%), the majority of whom (58.3%) maintained their preoperative hearing level. There was no perioperative mortality. One patient (4.5%) experienced a postoperative cerebrospinal fluid leak. After surgery, all patients did not recover the function of the preoperatively paralyzed lower cranial nerves. A new deficit of one or more of the lower cranial nerves was recorded in 50% of cases. So far, no patient has experienced recurrence during the follow-up period as ascertained by computed tomography or magnetic resonance imaging. CONCLUSIONS: Surgical resection is the treatment of choice for jugular foramen schwannomas. The POTS approach allowed single-stage, total tumor removal with preservation of the facial nerve and of the middle and inner ear functions in the majority of cases. Despite the advances in skull base surgery, new postoperative lower cranial nerve deficits still represent a challenge.     

颞下经岩尖-小脑幕入路手术的显微解剖研究

目的 为颞下经岩骨入路手术处理斜坡及脑干腹侧病灶提供解剖学资料。方法 模拟颞下经岩尖—小脑幕入路的手术操作,在手术显微镜下对20侧(10具)福尔马林固定的国人成年带颈头颅标本进行解剖,并观测各主要解剖结构的相互关系。结果 颞下硬脑膜外经前内侧的三叉神经压迹、外侧的岩浅大神经沟及岩上窦所形成的三角区磨削岩骨尖。其周围结构的测量结果为:上半规管垂直于岩骨嵴,位于弓状隆起下方,耳蜗位于内听道前方、岩骨颈内动脉膝后方,内听道位于上半规管与岩浅大神经夹角中央。20侧中有2侧面神经膝裸露,耳蜗至膝状神经节的距离约为3.30 mm±0.79 mm,耳蜗距颈内动脉膝约2.48 mm±1.14 mm,内听道距岩斜缝约16.03 mm±1.94 mm,颈内动脉水平段距岩上窦约10.73 mm±2.00 mm。结论 颞下经岩尖—小脑幕入路能增加岩斜坡及脑干腹侧的显露,但显露范围有限,且需一定程度的颞叶牵拉。同时可能因为不熟悉解剖而误伤耳蜗、颈内动脉及第Ⅶ脑神经、第Ⅷ脑神经,选择应用时应审慎考虑。     

Extracranial head and neck schwannomas: a review of 8 years experience

Schwannomas of the head and neck are uncommon tumors that arise from cranial, peripheral or autonomic nerves. In this study we review a series of 52 cases of schwannoma originating in the head and neck region over an 8-year period. All the tumors were benign, with the exception of one malignant schwannoma. The age range of the patients studied was 13-76 years and there was a predilection for males. Twenty-five schwannomas occurred in the scalp, face and external ear canal, 9 in the oral or nasal cavity and 18 in the neck. Seven cases of neck schwannoma originating from the major nerve system were found in the parapharyngeal space, all of which were located in the post-styloid compartment. Cervical plexus schwannomas originated either in the peripheral nerves or in an unidentified area of the nervous system; seven tumors were found in the posterior triangle of the neck and two in the anterior triangle. Two of the tumors originating in the brachial plexus were located in the posterior neck and one in the anterior neck. Tumors originating in the vagus nerve or sympathetic chain were all located in the anterior triangle of the neck.     

Extracranial Head and Neck Schwannomas: A Review of 8 Years Experience

Schwannomas of the head and neck are uncommon tumors that arise from cranial, peripheral or autonomic nerves. In this study we review a series of 52 cases of schwannoma originating in the head and neck region over an 8-year period. All the tumors were benign, with the exception of one malignant schwannoma. The age range of the patients studied was 13-76 years and there was a predilection for males. Twenty-five schwannomas occurred in the scalp, face and external ear canal, 9 in the oral or nasal cavity and 18 in the neck. Seven cases of neck schwannoma originating from the major nerve system were found in the parapharyngeal space, all of which were located in the post-styloid compartment. Cervical plexus schwannomas originated either in the peripheral nerves or in an unidentified area of the nervous system; seven tumors were found in the posterior triangle of the neck and two in the anterior triangle. Two of the tumors originating in the brachial plexus were located in the posterior neck and one in the anterior neck. Tumors originating in the vagus nerve or sympathetic chain were all located in the anterior triangle of the neck.     

Intracanalicular schwannoma of the facial nerve: a manifestation of neurofibromatosis type 2

Primary facial nerve tumors, which are relatively uncommon, can present a diagnostic dilemma based on their location and variable pattern of symptoms. Of primary cranial nerve tumors, schwannomas of the facial nerve rank third in frequency after those of the eighth and fifth cranial nerves. We report an illustrative case of an intracanalicular schwannoma associated with several central nervous system tumors, consistent with neurofibromatosis type 2. Initially assumed to be an eighth cranial nerve tumor, the schwannoma was found intraoperatively to arise from the facial nerve. Early diagnosis and treatment enabled excision of the tumor without sacrifice of the facial nerve. Facial nerve schwannomas can resemble acoustic schwannomas in their clinical presentation. Only a heightened level of clinical vigilance will point to the correct diagnosis and result in an optimal therapeutic outcome for patients with these rare tumors.